CVE-2026-57249: Foxit PDF Reader and Editor Use-After-Free Vulnerability (CVSS 7.8)

Technical summary

CVE-2026-57249 is a use-after-free vulnerability (CWE-416) affecting Foxit PDF Editor and PDF Reader on Windows systems. The flaw exists in the PDF parsing and form handling logic: when a specially crafted PDF file triggers the annotation reset followed by a form reset additional action, the application re-enters the form processing routine and attempts to access objects that have been freed from memory. This classic memory safety issue can manifest as a denial of service through application termination, and depending on memory layout and attacker sophistication, could potentially be leveraged for code execution. The CVSS 3.1 score of 7.8 (HIGH) reflects the combination of local attack vector, low attack complexity, no privilege requirement, user interaction needed, and impact to confidentiality, integrity, and availability.

Business impact

This vulnerability creates operational disruption risk for organizations whose employees use Foxit products to handle PDF documents. A user opening a malicious PDF attachment—whether from email, a compromised website, or an untrusted source—will experience application crashes that interrupt workflow. In more concerning scenarios, if the vulnerability is weaponized for code execution, an attacker could gain the same privileges as the user opening the document, potentially leading to lateral movement, data theft, or installation of persistent malware. For organizations relying on Foxit as a critical document processing tool, widespread exploitation could compound into business continuity issues.

Affected systems

The vulnerability affects Foxit PDF Editor and Foxit PDF Reader on Microsoft Windows. Users of these applications are at risk if they open untrusted or adversary-controlled PDF files. The vulnerability does not affect other PDF readers or editors unless they use the same underlying code; however, organizations should verify which Foxit product versions are deployed across their environment. Verify against the vendor advisory for specific affected version numbers and availability of patches.

Exploitability

Exploitation requires crafting a malicious PDF file with specific annotation reset and form reset actions, then delivering it to a user. The attack surface is broad because PDF files are ubiquitous in business and personal use, and users routinely open documents from semi-trusted sources. No special privileges or system access are needed to trigger the vulnerability. The primary barrier is user interaction—the victim must open the PDF—making social engineering or phishing vectors the likely delivery mechanism. Given the relative ease of creating a malicious PDF and the commonality of PDF-opening workflows, this vulnerability should be considered exploitable in real-world scenarios, though it is not yet included in the CISA Known Exploited Vulnerabilities catalog as of the publication date.

Remediation

Foxit has released patches to address this vulnerability; users should consult the Foxit security advisory and check for available updates to PDF Editor and PDF Reader. Patching should be prioritized for all systems where these applications are deployed. Until patches are applied, organizations should implement defensive measures: educate users to avoid opening PDF files from untrusted sources, configure email gateway filtering to block suspicious attachments, and consider disabling or restricting form functionality in Foxit if business requirements permit. Web-based PDF viewers may reduce risk if users can be directed to use them for untrusted documents.

Patch guidance

Foxit will provide specific patch versions and update procedures through their official security advisory. Administrators should: (1) review the Foxit advisory to identify which versions of PDF Editor and PDF Reader are affected and which versions contain the fix, (2) test patches in a non-production environment before broad rollout, (3) prioritize patching for systems used by high-risk users (executives, finance, legal) who may receive targeted phishing, and (4) verify patch installation across the organization. Check the vendor advisory for exact version numbers and remediation steps.

Detection guidance

Endpoint detection and response (EDR) tools should monitor for unexpected crashes of Foxit PDF Editor and PDF Reader processes, particularly when correlated with file access events. Security teams can also track the opening of suspicious PDF files from external sources and monitor for process behavior anomalies such as memory access violations or attempts to write to unexpected memory regions. Network-based detection is limited unless PDFs are scanned in transit; however, email gateways should flag PDFs with embedded scripting or complex form actions as potentially suspicious. Enable logging of application crashes and correlate with user and file information to identify potential exploitation attempts.

Why prioritize this

This vulnerability merits HIGH priority remediation due to several converging factors: (1) the use-after-free nature of the flaw presents both denial-of-service and potential code-execution risks, (2) Foxit products are widely used across enterprises and small businesses for document handling, (3) the attack requires only user interaction with a PDF, a routine activity in most organizations, (4) the attack vector is local but the delivery mechanism (email, web) is remote and scalable, and (5) the CVSS 7.8 score reflects significant impact across confidentiality, integrity, and availability. Organizations should treat this as a near-term patching priority, particularly for users handling sensitive or external communications.

Risk score, explained

The CVSS 3.1 score of 7.8 (HIGH) reflects: Attack Vector (Local)—the attacker must cause a user to open a file on their system; Attack Complexity (Low)—no special conditions or timing required; Privileges Required (None)—no elevated access needed; User Interaction (Required)—the victim must open the PDF; Scope (Unchanged)—impact is limited to the affected Foxit process and user privileges; Confidentiality (High)—potential for data exfiltration if code execution is achieved; Integrity (High)—potential for modification of files or process memory; Availability (High)—application crashes and potential system instability. The score appropriately captures the blend of ease of exploitation and severity of potential impact.

Frequently asked questions